Fluid-pressure brake



April z, 1929. Q FARMER 1,707,259

FLUID PRESSURE BRAKE Filed 001*...21. 1926 ll IO [2 J INVENTOR CLYDE. C. FARMER BY%W ATTORNEY hllTED STATES PATENT OFFICE.

tfllhE C. FAR-IE3, O1" PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO THE WEB'IING- IHQUBE AIR BRAKE OOHPAH'Y, OI WILHEBDING, PENNSYLVANIA, A CORI'OBATIOH ill" PENNSYLVANIA.

ILUID-PBESBUBE nnann Application filed October 21, 1928; Serial No. 143,154.

"this invention relates to fluid pressure hashes, and more articularly to means for retaining fluid on or pressure in the brake tinder, in the operation of releasing the on i h the running of railwa v trains, when dohdihp' grades, it is desirable to retain a o thin degree of fluid pressure in the brake ihdcrs when the brake pipe pressure is incised, in order to permit the recharge of the auxiliary reservoirs without releasing the hashes.

"lithe principal object of my invention is to irovide means, under the control of'the engiivherehy the brake cylinder pressure re- .upg means may be out in for operation on es, and out out for operation in level road t 'lliilhm the accompan ing drawing, the single time in a view o a fluid pressure brake pincnh showing my invention applied etc. a i shown in the drawing, the brake equip merit inn comprise a triple valve device It, connects to the usual brake pipe 2, an auxihury reservoir 3, a retaining valve device 4, noted to the triple valve brake cylinder at", pipe 5, and a control valve device ti. a control valve device 6 may comprise a casing containing a valve piston 7, having at t L l i side a chamber 8 connected to the atoms re through an exhaust incite side, when the va ve piston 2' is in moment with a seat ring 12, a chamber 10. 21th t the inner area of said seat ring, in constant ccnnnunication with the brake pipe 2, and

chainhor 11, at the outer area of the seat ring h is connected to chamber 8, at the opposite oi valve 7, by way of port 13.

when the valve piston 7 is in the opposite hi. tion to that shown in the drawing and hug against a gasket 14, the chambers 10 it. are connected together and the upper oil port 13 is closed. lithe control valve device 6 also includes a valve 15, contained in chamber 16 and oper chic hy the valve piston 7, for controlling "whnnnnication from the brake o linden: can pipe ti to the atmosphere, t rough the hunt part9 h spun 17, contained in chamber 8, is adapind to liold the valve 7 seated against the i ring 12, unless the brake pipe pressure hcreased above a predetermined degree,

rt 9 and at tho In operation, it is proposed that a lower hrake pipe pressure he carried when operatmg on a grade, than is carried when operating on alevel, such, for example, as 70 pounds brake pipe pressure in gradc'service and 90 undo brake pipe pressure in level service.

The control valve device 6, is shown in the drawing as in the operative position for grade service, the brake pipe pressure of 70 pounds for grade service, acting in chamber 1t) against the valve piston 7, being insufiicient to shift said valve piston away from the seat ring 12 against the pressure of spring 17.

The valve 15 is hold seated by the iressure of spring ili, so that communication ,twccn the triple valve brake cylinder exhaust pipe 5 and the atmosphere, through exhaust port 9, is closed. i

Thus, in grade service, when the triple valve device is shifted to release position, fluid under pressure from the brake cylinder can only vent through the retaining valve device 4, and thus a certain de es of pressure is retained in said brake cy inder while the auxiliary reservoir 3 is being recharged.

If it IS desired to operate the train on a level road, the pressure of the fluid in the hralre pipe Q is increased above the '20 pounds employed in grade cervica and therein the pressure in chamber is increased so as to overcome the picssurc of spring 17. The valve piston t" is therefore moved from ongagement "with the scat ring 12, exposing the u 1 area of said valve piston to brake pipe pressur n which causes a rapid movement of said valve piston to its seat against the gasket 14, in which position the upper end of'pasan e iii is ciosed.

"he upward movement of valve piston 7 causes the valve to be 0 nod, so that in releasing the brakes, when t e triple valve device moves to release position, the brake cylinder exhaust pipe 5 is connected directly to the stratosphere through chamber 8 and onhaust port ii, so that the retaining valve device 4 is not effective to retain pressure in the brake cylinder. A

With the control valve device 6 in ition for operation in level road service, in order to ad ust ilhl'l operation on a grade, the arts of the control valve are so pro rtioned t at it is necessary to reduce the ra e pipe pressure below the equalizing point before downward movement of the valve piston 7 will boob fected, such as a reduction in excess of 23 pounds from the 70 pounds brake pipe pressure. when the lower brake pipe pressure is obtained, the pressure of spring 17 is sulficient to start the valve piston 7 movin away from the gasket 14 towards the seat ring 12. The initial downward movement of said valve opens the connection between chamber 8 and passage 13 so that fluid at brake pipe pressure in chambers 10 and 11 may flow into chamber 8 and supplement the pressure of spring 17 in pushing the valve 7 to its seat 12. The valve piston 7 then quickly moves down and seals against seat ring 12. Chamber 11 is then connected to atmosphere through the exhaust port 9.

The movement of valve piston 7 to its lower position against the seat ring 12 permits the spring 18 to seat the valve 15 so as to close communication between the triple valve brake cylinder exhaust pi e 5 and the atmospheric exhaust rt 9, so t at the exhaust from the brake cy inder is then controlled by the retaining valve device 4.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. In a fluid ressure brake, the combination with a hraie pipe, brake cylinder, and triple valve devioe,-o a valve device for contro ling communication from the brake cylinder exhaust port of said triple valve device to an atmospheric exhaust port and operated upon an increase in brake pipe pressure above a normal pressure carried in the brake pe for opening communication from the rake cylinder exhaust rt to said atmospheric exhaust port, sai valve device being operated only upon a reduction in brake pipe ressure below the normal equalizin int or closing communication from said rake cylinder exhaust port to said atmospheric exhaust port.

2. In a fluid pressure brake, the combination with a brake cylinder, brake pi and tri le valve device, of a valve device El contro linfi communication from the brake cylinder ex aust port of said triple valve device to an atmosp eric exhaust port and operated at one normal brake pipe pressure for closing communication from the brake cylinder exhaust port to the atmospheric exhaust, at another higher normal brake pipe pressure for opening communication from the brake cylinder exhaust port to the atmospheric exhaust port, and operated upon a predetermined reduction in brake pipe pressure below said higher normal brake pipe pressure for closing communication from said brake c 'lindcr exhaus't port to the atmospheric ex aust'port.

In testimony whereof I have hereunto set my hand.

CLYDE C. FARMER. 

